(3ds max) Delete some geometry from a secondary UV channel?

This is more of a 3ds max question, is there a way to remove geometry from a second UV map, or any UV map for that matter? I’m using the first is for a base texture and the second is for a skin/paint that goes on top that only certain parts of the mesh will need and I need all geometry in the second UV facing a the same direction.
I know speedtree has some capability to use a secondary UV to add a texture at the bottom or top of the tree only and make it not tile beyond that, does anyone know how?